buffer too small

Jim Graham james.graham at oracle.com
Tue Mar 8 21:43:47 UTC 2016


I think I see the issue.

In the code that calls maskTex.update(...) it passes 
maskTex.physicalWidth() as the scan stride of the buffer, but the scan 
stride of the buffer is based on the content size, not the physical 
size.  Thus, the checkUpdateParams() method overestimates how many bytes 
are consumed by the operation.

Changing that to maskTex.getContentWidth() should be fine...

			...jim

On 3/8/16 6:14 AM, Johan Vos wrote:
> We got a number of bug reports (on Android and iOS) reported by developers
> using large images:
>
> java.lang.IllegalArgumentException: Upload requires 2475266 elements, but
> only 1549938 elements remain in the buffer
>
> at com.sun.prism.impl.BaseTexture.checkUpdateParams(BaseTexture.java:354)
>
> at com.sun.prism.es2.ES2Texture.update(ES2Texture.java:640)
>
> at com.sun.prism.impl.BaseContext.flushVertexBuffer(BaseContext.java:106)
>
> at com.sun.prism.impl.BaseContext.updateMaskTexture(BaseContext.java:248)
>
> at
> com.sun.prism.impl.ps.BaseShaderGraphics.renderShape(BaseShaderGraphics.java:482)
>
>
> I traced this down to the following:
>
> initially, a buffer of [1024 * 1024] is allocated by
> BaseContext.validateMaskTexture. When the MaskData becomes bigger than 1024
> (w or h), a new buffer is allocated with capacity [newTexW * newTexH] with
> newTexW and newTexH the new width/height that are passed when creating a
> new Texture. However, the physical size of the texture can be different --
> e.g.
>
> ES2Texture.create (ES2Context, PixelFormat, WrapMode, int, int, bool) will
> in some cases set the real texWidth/height to the next power of 2.
>
> Subsequently, in next rendering loops when the Texture needs to be updated,
> it is checked whether the capacity of the buffer is large enough to hold
> the texture. In this case, the physical width is passed and the buffer is
> not large enough.
>
> Adding the following two lines in BaseContext.validateMaskTexture() (line
> 220) fixes the problem:
>
>              newTexW = Math.max(newTexW, maskTex.getPhysicalWidth());
>
>              newTexH = Math.max(newTexH, maskTex.getPhysicalHeight());
>
> Using this patch, the size of the buffer will take the physical size of the
> texture into account. I'm not sure this is the best approach though.
>
> - Johan
>


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